Key lever



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June 2, 1959 Filed Sept. 23, 1958 S. B. TIBBLING June 2, 1959 KEY LEVER 2 Sheet S Sheet 2 Filed Sept. 23, 1958 INVENTOR. STIG B. TIBBLING BY V K-Qfl ATTORNEY United States Patent KEY LEVER Stig B. Tibbling, Carmel, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Application September 23, 1958, Serial No. 762,717 6 Claims. (Cl. 197-106) This invention relates to typewriters, and more particularly to key levers for actuating type bars of a typewriter.

The key levers of a typewriter are usually pivotally supported at one end and each is provided at its opposite end with a button which may be depressed manually for rocking the key lever and effecting an actuating of a type bar. Each key lever is usually held in a raised position by a coil type spring connected between the free end of the lever and the frame of the typewriter. The pivotal support for the key levers ordinarily consists of a wire or rod extending through openings in the levers. With such an arrangement, it is difficult to remove one of the key levers if this should be desired.

By providing a key lever with a forked portion at its pivotal end fitting over a pivot member that is rectangular in cross section, the spring action for holding the lever in its normal position may be obtained from the action of the forked portion against the upper and lower surfaces of the pivot member. A depression of the key lever results in a spreading of the fork arms and an increase in spring tension which returns the key lever to normal position as soon as the force holding it down is released. With the spring incorporated in the structure of the key lever, the usual spring may be dispensed with, thereby reducing the number of parts and the labor involved in assembling them.

The mounting of the key lever on the pivot member, or the removal of one of the levers from the pivot member, may be accomplished by simply moving the lever longitudinally in a direction perpendicular to the pivot member so as to force the latter between the fork arms or to remove it from between them. A notch may be formed in one of the fork arms for receiving a portion of the pivot member and holding the lever in place. The same result may be obtained by providing a projection on each fork arm extending toward the other arm, the projections being spaced from each other so that one engages an upper corner of the pivot member while the other engages the diametrically opposite lower corner. A curved surface is formed on the projecting portion adjacent the end of the fork arm so that a camming action is obtained for separating the arms when the lever is forced longitudinally against the pivot member.

An object of this invention is to provide an improved key lever mechanism for a key operated machine.

Another object is to provide an improved key lever which cooperates with a pivot member in such a way that a spring action is produced in the lever when depressed, tending to return it to normal position.

Still another object is to provide a key lever which can be mounted upon or removed from a pivot member by moving it longitudinally relative to the pivot member.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode,

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which has been contemplated, of applying that principle.

In the drawings:

Figure 1 is a side elevational viewof the improved key lever in nomal position, anda cam which is movable by the lever into engagement with a power roll for driving a type bar.

Figure 2 is a view likeFigure 1 but showing the key lever depressed and the cam with connected parts being driven by the power roll.

Figure 3 is an enlarged view of a portion of the key lever in a depressed position.

Figure 4 is a view like Figure 3 but showing another form of key lever.

Referring to the drawings it will be noted that there is shown a key lever 1 mounted at one end upon a pivot member 2 and carrying a key button 3 adjacent its other end. Only one key lever is shown but there may be others like it forming the keyboard of a typewriter. The pivot member 2 is of rectangular shape in cross section and extends transversely of the keyboard through flanges 4 of a slotted member 5.

The pivoted end of each key lever is slotted at 6 to form arms 7 and 8 between which the pivot member is received. As shown in Figures 1 to 3, the arm 8 is provided with a notch 10 which receives the lower portion of the pivot member 2 and limits the insertion of the latter into the slot 6. With the key lever mounted on the pivot member in its normal position as shown in Figure 1, the lower edge of the arm 7 and the bottom of the notch 10 have full contact with the top and bottom surfaces, respectively, of the pivot member 2. When the key lever is depressed by manual actuation of the button 3, the top front and lower rear edges of the pivot member act on the arms 7 and 8 to force them apart and produce a spring tension which tends to return the key lever to its normal position. The portion of the arm 8 between the notch 10 and the rear end of the arm is curved as shown at 12 to provide a cam surface which acts on the pivot member to force the arms 7 and 8 apart to permit mounting or removal of the lever from the pivot member. At the front end of the lever is a guide member 14 having slots 15 through which the levers extend to be guided in a vertical direction.

To mount a key lever on the pivot member, it is only necessary to insert the forward end of the lever through one of the slots 15 until its rear end can be moved between a pair of flanges 4 to a position in which the slot 6 is opposite the pivot member. The lever is then moved rearwardly, causing the member 2 to act between the lower edge of the arm 7 and the curved surface 12 on the arm 8, thereby forcing the arms apart to admit the pivot member into the slot 6 until it drops into the notch 10. Removal of a key lever may be effected by simply moving it forwardly until it is free of the pivot member and can be swung upwardly to a position in which it may be withdrawn from the slot 15..

Associated with the key lever is a mechanism, generally designated 16, which is operable in response to actuation of the lever for driving a type bar 21 into engagement with a platen 23. The mechanism 16 is like that shown in Patent 2,723,740 issued to T. H. Toeppen. It will be appreciated that the mechanism may be of any other type and need not be limited to the actuation of a type bar. The mechanism of any key operated machine could just as well be controlled by key levers like that described above. As shown herein, the mechanism 16 comprises a crank arm 17 pivotally supported at 18 and having a cam 19 pivotally connected thereto by a stud 20. The cam is normally held in an inactive position by a spring 22 connected between an car on the cam and a lug on the crank arm 17. Arranged above a tail portion of the cam is an operating element 24 which is 3. pivotally and slidably supported on a stud carried by a projecting portion of the crank arm 17. The element 24 is urged in a clockwise direction about the stud 25 by a spring 26 connected between ears on the element and the crank arm 17. Movement of the operating element in a clockwise direction is limited by a flange 27 on the crank arm 17. The spring 26 operates normally to hold the element 24 against the flange 27 and in a position with the stud 25 at the right end of a slot 28 through which the stud extends. At the lower edge of the operating element is a flange 30 which is engaged by the tail portion of the cam 19 for limiting the rocking of the latter in a counter-clockwise direction under the action of the spring 22. Formed on the upper edge of the operating element 24 is a flange 31 in a position to be engaged by a downwardly projecting portion 32 on the lever 1 when the latter is depressed.

The cam 19 is provided with a serrated surface 34 which is spaced from the pivot 20 distances increasing progressively from the left edge of the cam surface to the right edge. Arranged closely adjacent to the cam surface is a power roll 35 which rotates continuously in the direction shown by the arrow.

Upon depressing the key lever 1, the element 24 is moved against the tail of the cam 19 to rock the latter in a direction to engage the cam surface 34 with the power roll 35. The cam is then driven by the power roll about the pivot 20, and the increasing radius of the cam causes the pivot 20 to be moved away from the power roll and cause a rocking of the crank arm 17 about its pivot 18 against the action of a spring 36 to drive the type bar toward the platen. Before engagement with the platen takes place, the cam 19 leaves the power roll and is returned by the spring 22 to the position shown in Figure l. The type bar continues to travel due to the inertia produced until engagement with the platen takes place.

There is shown in Figure 4 a key lever 40 which differs slightly in shape from lever 1. In this case an upper fork arm 41 is provided with a shoulder 42 which is engaged by the pivot member 2 for limiting insertion of the latter between the fork arms. The lower fork arm 43 is provided at its end with an upwardly projecting curved portion 44 like that on lever 1 for holding the lever on the pivot member as shown in Figure 4 but permitting removal of the lever by forcing it forwardly. The upper-edge of the fork arm 43 is formed on a straight line except for the projecting portion 44. During the actuation of the key lever 40, bearing takes place only at the shoulder 42 and at the lower front edge of the projecting portion 44. It will be seen that only a small shoulder 42 is required since its position relative to the member 2 does not change when the key lever is depressed.

While there have been shown and described the fundamental novel features of the invention as applied to a preferred embodiment and a modification thereof, it will be understood that it may be modified and embodied in various other forms without departing from the spirit of the invention. It is the intention to be limited only as indicated by the scope of the following claims.

I claim:

1. A key lever mechanism for a key operated machine comprising, in combination, an elongated member slotted at one end to provide fork arms thereon, a pivot member rectangular in cross section and receivable between said fork arms, adjacent edges of said fork arms being shaped to engage normally opposite surfaces on said pivot member, and a key button mounted upon said elongated member adjacent its other end for manual actuation to rock said elongated member from a normal position about said pivot member, said fork arms being forced apart by diagonally opposite edges of said pivot member when said elongated member is rocked, thereby producing a spring tension tending to return said elongated member to its normal position.

2. A key lever mechanism for a key operated machine comprising, in combination, an elongated member slotted at one end to provide fork arms thereon, a pivot member rectangular in cross section and receivable between said fork arms, a notch in one of said arms adapted to receive a portion of said pivot member for limiting insertion of the latter between said arms, the bottom of said notch and the edge of the other arm opposite said notch being shaped to engage normally opposite surfaces on said pivot member, and a key button mounted upon said elongated member to permit manual actuation of the latter from a normal position about said pivot member, said fork arms being forced apart by diagonally opposite edges of said pivot member when said elongated member is actuated, thereby producing a spring tension tending to return said elongated member to its normal position.

3. The key lever mechanism of claim 2 in which the portion of said notched arm between its end and the adjacent edge of said notch is curved to provide a cam surface cooperating with said pivot member to force said arms apart as said elongated member is moved longitudinally relative to said pivot member.

4. A key lever mechanism for a key operated machine comprising, in combination, an elongated member slotted at one end to provide fork arms thereon, a pivot member rectangular in cross section and receivable be tween said fork arms, a shoulder on one of said arms engageable by said pivot member adjacent one of its edges for limiting insertion of said member between said arms, a projecting portion on the other of said arms engageable with said pivot member adjacent its diagonally opposite edge for holding said pivot member normally against withdrawal from between said arms, and a button mounted upon said elongated member to permit manual actuation of the latter from a normal position about said pivot member, said fork arms being forced apart by diagonally opposite edges of said pivot member when said elongated member is actuated, thereby producing a spring tension tending to return said elongated member to its normal position.

5. The mechanism of claim 4 in which said projecting portion is provided with a curved surface cooperating with said pivot member to cam said arms apart upon moving said elongated member longitudinally relative to said pivot member.

6. A key lever mechanism for a key operated machine comprising, in combination, an elongated member slotted at one end to provide fork arms thereon, a pivot member rectangular in cross section and receivable between said fork arms, the adjacent edges of said fork arms normally engaging opposite surfaces of said pivot member and holding said key lever in a horizontal position, a shoulder on one of said arms engageable by the upper forward edge of said pivot member for limiting insertion of the latter between said arms, a projecting portion on the other of said arms engageable withsai'd pivot member adjacent its diagonally opposite edge for holding said pivot member normally against withdrawal from between said arms, and a button mounted upon said elongated member to permit manual depression of the latter from its normal position about said pivot member, said fork arms being forced apart by diagonally opposite edges of said pivot member when said elongated member is depressed, thereby producing a spring tension tending to return said elongated member to its normal position.

No references cited. 

